John Sayers' Recording Studio Design Forum Archive

Hey.
I'm planning on building Holtz resonator side walls in my control room.
http://www.johnlsayers.com/phpBB2/viewtopic.php?t=3806
I've been playing around with the calculator and my question is:
I have some "boards" 4"x8" and get really good results in the Helmholtz calculator. For instance with a 300mm depth from wall and a slot width of 1 mm the center frequenzy is 54 Hz. But will this work in real life? And can i vary from 4"x8" to 1"x8" and 1/2"x4 ?? Anyone who have tried with so massive slats?

I've not tried anything close to that, and I doubt John has either; he claims slot absorbers (Helmholtz) don't work much below 150 hZ, and I've not tried it myself so can't argue one way or the other.

Maintaining a 1 mm gap between boards should be nearly impossible, especially with that thick a board; I think you'd be better off with panel traps at that low frequency. Placement is important too - for panel traps they need to go at highest sound PRESSURE, not velocity... Steve

Hmmmm... So i guess it is waste of time, material or something...
As you can see from the link http://www.johnlsayers.com/phpBB2/viewtopic.php?t=3806
i will have hangers at the false rear wall...
Guess i have to go for the "standard" slot wall after a little mesurement of the room.. Would have been interesting, though..

Anyone who have tried with so massive slats?

yup - but I stood them vertically so it was a diffusor as well.
I stepped each slat in a similar way to a diffusor.

like this.

cheers
john

Cool. And the results of your wall. Did it work?. Its gonna be a sort of diffusor anyway, because of the vary in material thickness, width and so... What do you think John about having the 4"x8" in the first 2 or 3 rows of a helmotz??? Know its gonna be difficult to keep 1 mm slot all the way, but does that really matter?